29 September 2011

First Widespread Autumn Chill Headed For the Eastern U.S.

Posted by Dan Satterfield

Surface pressures and temperatures from the NOAA Global Forecast System (GFS) model. Maps ctsy. Univ. of Oklahoma meteorology dept.


The ridge of high pressure in the upper levels will keep the Rockies warm and dry while the east cools down, but even this is about to change soon.

Get ready for a cool down if you live in the East! For many folks from the Plains to the Deep South, this weekend will be the first time they have to turn on the heat and it will be a stark reminder that the hot summer of 2011 is in the history books. The NWP models are in close agreement that as the cold core low over the Great Lakes departs, it will drag down a batch of cool continental air from Northern Canada.

The map above shows the surface temperatures for sunrise Saturday and lows will reach the 40’s as far south as GA and Alabama, while a frost is possible perhaps as far south as Kentucky. Ahead of this front the very warm weather continues with International Falls, MN. reaching a record 81°F (27°C) on Wednesday afternoon and Montana seeing highs in the 80’s as well. The long-range guidance is indicating a pattern shift in about a week that will finally bring in cooler weather to the nation from the Rockies westward, while it warms back up a little east of the Mississippi.

All in all, there is no doubt that real autumn weather is about to arrive.